What is the quantity of a substance in chemistry, explained in detail.

The quantity of matter is one of the seven basic physical quantities in the International System of Units (the seven basic physical quantities are: length, mass, time, current intensity, luminous intensity, temperature, and quantity of matter), and it is the same as the concepts of "length", "mass", "time", etc., and is an overall noun of a physical quantity. Its symbol is n, and the unit is mole (mol), which is referred to as mole.

The quantity of a substance is the ratio of the number of particles (n) (e.g., molecules, atoms, etc.) contained in a substance to Avogadro's constant (na), i.e., n=n na. It is a physical quantity that connects microscopic particles with macroscopic weighable matter.

It indicates the number of particles contained in a substance.

Definition of the quantity of matter: Represents a collection containing a certain number of particles. The number of particles of any substance contained in 1 mol is called Avogadro's constant, and the approximate value is NA

The quantity of matter is how many molecules, or ions, or atoms there are in a matter at the microscopic level. This is the best explanation to understand, oh, I hope it helps you.

It is a unit of measurement of matter.

The amount of the chemical substance: It is one of the seven basic physical quantities in the International System of Units, and its symbol is n, and the unit is moles (mol), referred to as moles. The amount of a substance is an indication of the number of particles (n) contained in the substance (e.g.

molecules, atoms, etc.) to Avogadro's constant (Na), i.e., n=n na.

1. The quantity of matter: It is a physical quantity that represents a large number of particles collectively, with the symbol n and the unit is moles (mol).

2. Mole: It is a unit of quantity of matter; Internationally, it is stipulated that the number of particles contained in a 1 molar particle collective is the same as the number of carbon atoms contained in kg c, which is about.

3. Avogadro's constant: The exact value of the number of particles of any particle of 1 mole, that is, the exact value of the number of particles of 1 mole, is represented by the symbol na, and the approximate value of na is.

The quantity of matter is a collection that represents a certain number of particles, the symbol is n, and the unit is moles (mol), which is a physical quantity that measures the number of particles contained in a substance.

The quantity of matter is used to describe microscopic particles, such as molecules, atoms, ions, protons, neutrons, electrons, etc. The amount of matter is one of the 7 basic units of the International System of Units.

The application of the quantity of matter in chemical experiments.

1.The amount of concentration of the substance.

1) Definition: The physical quantity of solute B contained in a unit volume of solution is expressed as the concentration of a substance called solute B.

2) Unit: mol l

3) The amount of the substance concentration = the amount of the solute of the substance The volume of the solution cb = nb v

2.Preparation of the amount and concentration of a certain substance.

1) Basic principle: according to the volume of the solution to be prepared and the amount and concentration of the solute, the mass or volume of the required solute is calculated by the method of calculating the quantity and concentration of the relevant substance, and the solute is diluted with solvent to the specified volume in the container, and the solution is to be prepared.

2) Precautions.

Use a volumetric flask with the same volume as the solution to be prepared.

It must be inspected for water leakage before use.

It cannot be dissolved directly in a volumetric flask.

The dissolved solution is transferred when it cools to room temperature.

When the volume is fixed, when the liquid level is 1 2cm away from the scale line, use a dropper, and observe the water addition by head-up method until the lowest part of the liquid level is tangent to the scale.

3.Solution dilution: C (concentrated solution) V (concentrated solution) = C (dilute solution) V (dilute solution).

The quantity of a chemical substance: is a physical quantity that represents a collective containing a certain number of particles, with the symbol n. The unit of quantity of matter is mole, referred to as mole, and the symbol is mol.

Internationally, 1mol is the amount of a substance that contains exactly the basic units of a system such as atoms or molecules.

Mole (mole), abbreviated as mole, formerly known as gram molecule, gram atom, symbol mol, is the unit of quantity of matter, is one of the seven basic units of the International System of Units. Every 1 mole of any substance (microscopic substance, such as molecules, atoms, etc.) contains the Avogadro constant (about one particle. When using moles, elementary particles should be specified and may be atoms, molecules, ions and other microscopic particles, or specific combinations of these microscopic particles.

The formula for calculating the quantity of a substance.

1. The amount of matter = the number of particles Avogadro's constant (n=n na).

2. The quantity of the substance = the mass of the substance The molar mass of the substance (n=m m).

3. The amount of matter = the volume of the gas The molar volume of the gas (n=v vm).

4. C = 1000ml L (density) W m.

Note: n(mol): the amount of the substance; n：

particle count; v(l): the volume of the substance; m(g mol): molar mass; w%：

The mass fraction of the solute in the solution, the mass percentage concentration = the mass of the solute The mass of the solution * 100%.

Answer: d; Because the ratio of the three ions in it is 1:1:2, and the ratio of potassium ions to sulfate ions in potassium sulfate is 2:1, when 1mol of potassium sulfate is added.

Potassium ion 1, sulfate is, but also to add, and the ratio of aluminum ion to sulfate ion in aluminum sulfate is 2:3, when adding 1mol of aluminum sulfate, it is exactly 1:1:

2, but the concentration of the two is not the same, so the volume ratio is 2:1. The problem requires a certain concentration, so you can say that you add one liter and use the concentration of one of the ions to calculate the amount of water.

The answer is d

1。The ratio of the mass of each atom in a molecule is the ratio of the number of atoms that make up the molecule. For example, the ratio of the amount of H atom to O atom matter in the H2O molecule is 2:

12。In the same way for ionic compounds, the ratio of the amount of matter of each ion is also the ratio of the number of ions that make up it, but it has no significance to compare it with the amount of matter of the whole compound. For example, the CaCl2 of calcium chloride 1mol, the chloride ion is 2mol, and the ratio of the amount of calcium chloride substance is 2:

13。A molecule is generally composed of multiple atoms, so the sum of the substances of the atoms is usually greater than the amount of the molecules. For example, if the H2O molecule has 1mol, the hydrogen atom has 2mol, and the oxygen atom has 1mol, then the sum of the substances of each atom is greater than 1mol.

1. The amount of interatomic matter in a molecule is determined by the subscript.

2. The amount of the ionic substance in the molecule should be equal to the sum of the corner marks multiplied by the amount of the molecule's substance.

3. This problem is not necessarily because it is necessary to distinguish between the molecular formula of monoatomic molecules and polyatomic molecules, and the monoatoms should be equal, such as noble gases. In the case of polyatomics, it should be the sum of the corner marks

The quantity of matter is a basic concept, a defining quantity, that is, a regulation.

The overall requirement of the chapter "The Quantity of Matter" is: "Five Quantities and Two Relations", as long as you remember the units of "five quantities", you can understand and remember the calculation formula.

1. These five quantities are: Avogadro's constant (mol), molar mass (g mol), gas molar volume (l mol), quantity concentration and density of matter (g mol).

2. For example: the molar mass is measured in units such as: g - mass, mol - the amount of the substance, g mol represents the mass divided by the amount of the substance.

Note when using: (1) In addition to the quantity and concentration of the substance, the physical quantity indicates the physical quantity of the same kind of particle (2) The molar volume of the gas has its own conditions and range: for the gas (gas mixture can also be used), it can be used under standard conditions.